The present invention relates generally to a bobbin for an inductive electronic component. More particularly, this invention relates to a bobbin that isolates the winding turns of an inductive electronic component on two separate sections of a winding member.
Referring to FIG. 1, a cross sectional view of an inductive electronic component 11 that utilizes a prior art bobbin 10 is shown. The bobbin 10 has a winding member 12 and an inner winding 14 that is wound about the winding axis 16 of the winding member 12. The inner winding 14 has winding layers 14A each stacked on top of one another. The problem with this design is the high level of voltage stress created between each layer 14A of the inner winding 14. To reduce the voltage stress between the layers 14A of the inner winding 14, layers of insulation 14B, such as insulation tape, are placed between each one of these layers 14A. Unfortunately, these layers of insulation 14B take up room on the bobbin 10 which reduces the number of layers 14A that can be placed on the inner winding 14. Also, each layer of insulation 14B must be accurately placed over each winding layer 14A, otherwise the layers 14A may contact each other which results in unwanted voltage stress.
If the inductive electronic component 11 is a transformer, the inductive electronic component 11 may also have an outer winding 20 that is wound co-centrically on top of the inner winding 14. Unfortunately, this outer winding 20 also creates a voltage stress with the layers 14A of the inner winding 14. Consequently, an insulation layer 20A of insulation tape must be placed between the inner winding 14 and the outer winding 20.
The prior art attempts to resolve voltage stress problems by placing the primary and secondary winding on separate horizontal sections of a bobbin or by applying each winding on a separate bobbin and attaching the bobbins to one another. However, because the primary and secondary windings are not wound co-centrically, there is poor coupling between the primary and secondary windings.
What is needed then is a bobbin that reduces voltage stress between winding layers of the inner winding while maintaining the inner and outer windings co-centric.